Workpiece clamps or chucks, such as electrostatic clamps or chucks (ESCs), are often utilized in the semiconductor industry for clamping workpieces or substrates during plasma-based or vacuum-based semiconductor processes such as ion implantation, etching, chemical vapor deposition (CVD), etc. Clamping capabilities of the ESCs, as well as workpiece temperature control, have proven to be quite valuable in processing semiconductor substrates or wafers, such as silicon wafers. A typical ESC, for example, comprises a dielectric layer positioned over a conductive electrode, wherein the semiconductor wafer is placed on a surface of the ESC (e.g., the wafer is placed on a surface of the dielectric layer). During semiconductor processing (e.g., ion implantation), a clamping voltage is typically applied between the wafer and the electrode, wherein the wafer is clamped against the chuck surface by electrostatic forces.
For certain ion implantation processes, heating of the workpiece via a heating of the ESC is desirable while the workpiece is subjected to an ion beam. As workpiece temperature control and accuracy continue to have greater importance during processing, an impact that the power from the ion beam has on wafer temperature is resulting in less accurate and less stable wafer temperatures, especially with higher-powered ion beams. Thermocouples that are embedded into the ESC for measuring temperature, however, have relatively slow response times, and are often not thermally coupled close enough to the wafer to provide adequate fast and accurate control of heated ESC. While thermocouples that are in contact with the wafer may provide fast temperature measurements, such contact thermocouples are difficult to implement and can result in higher particles and decreased reliability of the ion implantation system.